Think I broke my rear diff today...

[Phillzpeed]

Well, actually, I am pretty sure I did. I will know for sure tomorrow when we do some digging around and take the diff apart. It has been coming, so it is not a big surprise.
The good news is that it didn't totally break... The car is still drivable (although I don't dare drive it anymore), it's just making a HORRIBLE racket (clicking, griding, and banging from the rear), so hopefully there is no other damage.

I am thinking I will go with either the TRD TT Supra rear or stock 6speed rear... Any thoughts or suggestions fellas?

[TSopranoIS300]

damn Mike, sorry to hear....was the car originally a 5 speed or automatic?

go with what the SRT guys like isman, boosted4door (T72-2JZ), Redline, etc etc

they get the GS400 rear....havent heard anyone break those suckers

[T72-2JZ]

Hey Mike, you can locate a used 20,000-30,000 mile diff from almost any junk shop for like $300-$500.

[Phillzpeed]

damn Mike, sorry to hear....was the car originally a 5 speed or automatic?

go with what the SRT guys like isman, boosted4door (T72-2JZ), Redline, etc etc

they get the GS400 rear....havent heard anyone break those suckers


Thanks Marc.

The car was originally a 5 speed. I am actually kinda happy it went. I was really getting tired of the nearly non-existant 1st gear. Actaually, I think 55,000 miles of 325-400rwhp on that diff was pretty good...

I think the GS400 rear may be a good idea... Just need to do a little more research...

[Phillzpeed]

Hey Mike, you can locate a used 20,000-30,000 mile diff from almost any junk shop for like $300-$500.

Thanks Peter, I am going to look into that. Just need to decide which rear to use. I just did a bit more research and it appears as though alot of fabrication work is involved with any rear swap.

Oh well, I got all winter.

[LexIS307]

Good luck, sorry to hear that you broke your diff...too Much boost eh... :lol:

Best Wishes

[T72-2JZ]

Thanks Peter, I am going to look into that. Just need to decide which rear to use. I just did a bit more research and it appears as though alot of fabrication work is involved with any rear swap.

Oh well, I got all winter.

Hey Mike, When the car gets done i'll get under the car for you and take some pictures. if that doesn't help much i'll try and drive the car out there. My cousin lives in Ravenna so like 15-20 minutes from Akron? Goto car-parts.com I found like 5 different junkyards who had the differential. GS400, and the GS430's rear diff are identical 3.227(not 100%sure).

Gluck Mike.

[Phillzpeed]

Hey Mike, When the car gets done i'll get under the car for you and take some pictures. if that doesn't help much i'll try and drive the car out there. My cousin lives in Ravenna so like 15-20 minutes from Akron? Goto car-parts.com I found like 5 different junkyards who had the differential. GS400, and the GS430's rear diff are identical 3.227(not 100%sure).

Gluck Mike.

Thanks alot Peter, I am sure that will help tremendously! I am also pretty sure both are identical.

I talked to Guru22 (previous owner of my car), and discussed a few things about my options. He told me that in addition to the fabrication work, the angles of the driveshaft and diff have to be EXACT, and that even Peter Farrell got it wrong the first time and trashed a TT Supra diff after 500 miles. That of course did not make me feel any better about my friends and I attempting to do this...

It may be in my best interest to bite the bullet and have someone who has experience doing this do it.

[Bgwillyis300]

awww man so no long garage nights with pizza and beer this winter......Dayum! :sleep:

[SupraGOM]

hope she's back up and running soon mike...

[J-GTE]

in research which did you find more preferred? the TT supra or the GS4xx differential? i was thinking of doing this too. tried to search but didn't know what to look under. do i look up differentials, axles, rear clips, what?

[Phillzpeed]

in research which did you find more preferred? the TT supra or the GS4xx differential? i was thinking of doing this too. tried to search but didn't know what to look under. do i look up differentials, axles, rear clips, what?
Well, I have found that the GS400/430 rear is preferred for several reasons...

One, it is more widely available and alot cheaper. It also seems that the fabrication to fit this diff is a bit less involved. The gearing of 3.27 is pretty nice, even though the 3.13 of the Supra would be even better IMHO. The GS rear is an open diff thogh, so it would be in your best interest to swap in a TRD or Kaaz LSD while you are at it.

That is about all I can think of off the top of my head.

I will share more as I continue my search...

[JaysonMFK]

TRD Supra. lol

make it work and have no regrets later.

[J-GTE]

thanks for the info. really appreciate it.

[J-GTE]

i've been searching on my.is and i am still wondering what parts make-up the term GS400 rear or Supra rear? When i searched on car-parts.com they didn't have "gs400/supra rear."

[T72-2JZ]

One of the main reason's why some of the big Supra guys are swapping out there stocks to GS rear diff's is cause its easier to build boost with the GS rear differential.

J-GTE if your trying to look for the rear differential on car-parts.com its listed under rear differential and make sure they tell you the differential is 3.27 before shipping.

Btw Mike any word to the status of your car?

[TSopranoIS300]

One of the main reason's why some of the big Supra guys are swapping out there stocks to GS rear diff's is cause its easier to build boost with the GS rear differential.

J-GTE if your trying to look for the rear differential on car-parts.com its listed under rear differential and make sure they tell you the differential is 3.27 before shipping.

Btw Mike any word to the status of your car?

which "big Supra guys" never heard of ANY Supra's using Lexus GS rears....

just curious if you happen to know who/provide links

[T72-2JZ]

which "big Supra guys" never heard of ANY Supra's using Lexus GS rears....

just curious if you happen to know who/provide links

Sorry Marc I can't think of there names off hand. But i've spoke with Mo and someone over at tbko they both said the GS rear gearing is better for reaching boost.

[TSopranoIS300]

Sorry Marc I can't think of there names off hand. But i've spoke with Mo and someone over at tbko they both said the GS rear gearing is better for reaching boost.

yes, i've read that many times....for IS300 owners

but you said SUPRA owners, that I do not believe is true, as the Supra TT rear is proven to hold mega power....

[T72-2JZ]

never said the supra tt rear isn't strong we all know this, but that doesn't mean the GS rear isn't strong or just as strong.

i'll try and get a link/names just for u Marc :riaa:

[TSopranoIS300]

never said the supra tt rear isn't strong we all know this, but that doesn't mean the GS rear isn't strong or just as strong.

i'll try and get a link/names just for u Marc :riaa:

duh Peter..I just dont honestly believe any Supra guys have switched to GS rears....

[J-GTE]

T72-2JZ thanks for the clarification! So when doing the swap is it just the rear differential, what about the stock rear axles? Do they hold up pretty well with concerns to power? Or do you need to probably change those out as well?

[TeckniX]

In the meantime..you can buy this
http://cgi.ebay.com/ebaymotors/01-LEXUS-IS-300-AUTO-DIFFERENTIAL-W-DRIVE-LINE-OEM-50K_W0QQcmdZViewItemQQcategoryZ33731QQitemZ8006756 706QQrdZ1QQsspagenameZWDVW
$110 to still drive the car around isn't too bad ;)

[Phillzpeed]

In the meantime..you can buy this
http://cgi.ebay.com/ebaymotors/01-LEXUS-IS-300-AUTO-DIFFERENTIAL-W-DRIVE-LINE-OEM-50K_W0QQcmdZViewItemQQcategoryZ33731QQitemZ8006756 706QQrdZ1QQsspagenameZWDVW
$110 to still drive the car around isn't too bad ;)
Actually, my friend (Doodlebug to you .Netters) has an auto rear diff, and I am giving him my old DWP stock hood for the diff... we are going to install it this weekend, so I will get to drive my car again!!!!! Yippeee! lol

But, the auto diff is a 3.90, and with my 6 speed the gears are gonna be MAD short... Hell, they were bad enough with the 3.73 5 speed rear.


Oh well, at least I will be back on the road, and it also means I can drive it to TurboEast to have the GS rear put in this winter instead of having it hauled there...

[T72-2JZ]

T72-2JZ thanks for the clarification! So when doing the swap is it just the rear differential, what about the stock rear axles? Do they hold up pretty well with concerns to power? Or do you need to probably change those out as well?

they need to be changed aswell

[TSopranoIS300]

they need to be changed aswell

"should" but most dont..they just change out the carrier.....

[J-GTE]

so i take it just change them to whatever differential i find? if i decided to go with the GS rear, does it really matter if it came from an auto? because i'd be mating it with the v160 tranny.

[Phillzpeed]

UPDATE:

Well, we put in an auto rear yesterday. Swap went pretty well... took us about 4 hours or so. The shorter gearing isn't that noticably different from the 5 speed 3.73, but man, the acceleration is nuts, especially in 2nd-5th (can't even build boost in 1st it is so short LOL)!!!

Next step, take the car to Baltimore this winter for the GS4/Kaaz LSD. :)

[T72-2JZ]

Nice Mike, im jealous of your car super clean.

[Phillzpeed]

Thanks Peter... but it is I that am jealous.


Your car will be/is a beast! T72. I needn't say anymore. :)


Can't wait to see it in person next year.